First pregnancy test

This is my first pregnancy test. My husband and I have been ttc for 4
months. I am 34 years old. It's 2 days until AF and I couldn't wait any longer so I tested. I was discouraged when I got a bfn. I recently had light cramps yesterday and today so I thought it might have been implantation. Anyone with the same experience? How likely is it that's just not picking up the hcg hormone? I guess I'll just have to wait to see if AF comes in 2 days.